This invention relates generally to mobile working machines such as mobile cranes, mobile excavators and the like, and more particularly to high-speed mobile working machines comprising a vehicle chassis having a rotatable superstructure upon which is mounted the working device, a first engine for the high-speed drive of the vehicle, and a second engine for driving the working device.
It is understood in the art that high-speed mobile working machines must be capable of being driven on high-speed highways having minimum speed limits of at least 60 km. per hour, for example. Consequently, the first engine for driving the vehicle must have the required power for attaining these speeds, e.g., 120 H.P., while the second engine for driving the working device of the machine might require substantially less power, e.g., 60 H.P.
It should be apparent, therefore, that the aforementioned requirements necessitate a large investment in total engine capacity for the machine, at substantial cost, which capacity is inefficiently utilized in prior art machines because each engine is used only for its specialized task and is normally dormant when the other engine is in operation.